Grazing alfalfa (Medicago sativa L.) in summer would provide high quality forage during periods of low rainfall when other forages are in short supply. ‘Arc’ alfalfa, grown on fine‐loamy, mixed, mesic Fluventic Dystrochrept at Blacksburg, VA, was grazed by sheep following two hay cuts in 1982 and 1983 with six treatments: (i) no grazing with hay being cut at 1/10 bloom; (ii), (iii), and (iv) grazing began approximately 14 days after second hay cut and continued for 2, 4, and 6 weeks, respectively; (v) grazing began at early bud stage and continued for 10 days in 1982 and 7 days in 1983; and (vi) grazing began at early bloom and continued for 7 days. Following grazing, hay was cut on each treatment if regrowth reached 1/10 bloom stage before killing frost. No grazing was imposed in 1984 and hay was harvested three times from plots from all six treatments. Forage remaining after grazing for 2, 4, or 6 weeks was higher in percent leaf, in vitro dry matter digestibility, crude protein, Ca, Mg, and P concentration, and was lower in cell wall constituents than after grazing at early bud or bloom. Grazing for 4 and 6 weeks precluded fall hay harvest and increased weeds. Alfalfa yield in 1984 was reduced by grazing except grazing at early bloom. Yield was 8.5, 7.3, 7.1, 6.7, 7.3, and 8.7 Mg ha−1 for the six treatments, respectively. Weed encroachment generally increased with increased grazing duration (GD). Grazing could decrease productivity, especially as GD is lengthened, but may be less detrimental than previously supposed.
